The present invention relates to inductive battery charging systems, and more particularly, to the use of spiral/helical foil windings in an inductive charging probe that moves the outer foil windings of the probe closer to a heat sink, thereby improving thermal management.
The assignee of the present invention designs, develops and manufactures inductive battery charging systems for use in charging the propulsion batteries of electric vehicles. The inductive charging system is employed to charge the propulsion batteries of an electric vehicle. A charge station is coupled to a power source and has an extendable charging cord that is coupled to a charge probe. The charge probe comprises a primary core and a primary winding of a transformer and is inserted into a charge port disposed in the electric vehicle that comprises secondary core and secondary windings of the transformer. The charge port and the charge probe form an inductive coupler. The charge port is coupled by way of a charge controller that interfaces to the propulsion batteries of the electric vehicle to supply power thereto.
The closest prior art relating to the present invention is the use of a helical foil stack of windings in a planer transformer. The disadvantages of this type of transformer are that as the foil stack of windings grows in thickness, the losses in each foil windings increase because of the AC loss proximity effect.
There is a desire to produce inductive chargers that permits inductive coupling at very high charge rates or power charging levels, such as on the order of 120 KW or more. However, it has been found that, at 50 KW power charging levels and higher, overheating at the interface between the inductive charger and electric vehicle becomes a limiting factor. Providing for improved thermal management of the inductive coupler is necessary to help overcome this limitation if the power transfer goal is to be met.
Therefore, it is an objective of the present invention to provide for an inductive charging system that employs spiral/helical foil windings in an inductive charging probe that moves the outer foil windings of the probe closer to a heat sink, thereby improving the power handling capacity and thermal management of the system.